#include <stdio.h>

int main(int argc, char *argv[]) {

    double num,res;
    scanf("%lf", &num);
    if (num<1)
    {
        res = num;
        printf("y=%.2lf",res);
        
    }else if (1<=num&&num<10)
    {
        res = (num*2)-1;
        printf("y=%.2lf",res);
    }else if (10<=num)
    {
        res = (num*3)-11;
        printf("y=%.2lf",res);
    }
    
    return 0;
}